Thermostatic circuit controller



Jan. 14, 1936. R. J. PARSONS 2,028,077

THERMOSTATIC CIRCUIT CONTROLLER v Filed May 9, 1954 41 MMIII l 'Hgh [l:

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INVENTOR BY I l www Patented Jan. 14, 1936 UNITED STATES PATENT OFFICE THERMOSTATIC CIRCUIT CONTROLLER Application May 9, 1934, Serial No. 724,716

5 Claims.

This invention relates to electricity, more especially to circuit controllers, and particularly to circuit controllers governed by temperature, commonly known as thermostatic circuit controllers.

A principal object of this invention is to produce a device of the type specified which will be compact, easy to adjust, simple and inexpensive to manufacture, particularly free from a tendency to get out of order, and certain and powerful in its action.

. Other objects and advantages will appear as the description of the particular physical embodiment selected to illustrate the invention progresses, and the novel features will be particularly pointed out in the appended claims.

In describing the invention in detail and the particular physical embodiment selected to illustrate the invention, reference will be had to the accompanying drawing and the several views thereon, in which like characters of reference designate like parts throughout the several views, and in which:

Figure 1 is a front elevational view of a panel with a `thermostatic circuit controller of applicants invention in place thereon; Fig. 2 is a cross-sectional view of the device on the plane indicated bythe line II- II of Fig. 1,` viewed in the direction of the arrows at the ends of the line; Fig. 3 is a schematic or diagrammatic illustration of a circuit with which applicants thermostatic circuit controller is advantage- "ously used.

In the figures, numeral I designates a panel or mounting member upon which applicants device may be positioned. 'I'his panel is made of an insulating material as is usual.

Attached to the panel I, preferably by means of screws, as y2, is the magnet bar 3 made of magnetic material. The magnet bar 3 supports the electro-magnet 4, having the pole piece 5, by means of screws as 6.

Cooperating with the electro-magnet 4 and its pole piece 5 is the latch lever 1, pivoted at 8, and formed with the latch shoulder 9 at one end, and adjacent thereto, the contact face I0. Intermediate the pivot 8 and the latch shoulder 9 is the stop shoulder I I. To the right of the pivot as viewed in Fig. l., the pivot lever 1 is formed with a non-magnetic facing I2 to prevent the latch fromend of which seats in the depressed spring seat I5 of the member 3. The latch lever l also carries the manual grasping insulating button I6 provided with the finger guard Il and attached by means of the screw I8 to the lever. This manual 5 grasping button I6 enables a manual operation of the latch lever 'I without danger of receiving electric shock.

The magnet bar- 3 also supports the pivoted latch pivot supporting arm I9 attached as by 10 means of screws 20. This arm I9 also supports the contact post and pivot lever stop 2l.

A contact finger 22 is positioned to engage the contact'face I0 and contact face IIJ', being latched by the latch shoulder 9, and resiliently supported 15 by the contact finger carrying arm 23. The resilient support is formed by a bolt 24 having a head 25 on one side of the contact finger carrying arm 23 after passing through the arm and the contact nger surrounded by the contact nger spring 26 held in place by a washer 21 and a cotter pin 28. This construction is such that if contact finger 22 is latchedby latching shoulder 9 and contact finger carrying arm 23 moves to the left, as viewed in Fig. 1, then the contact ngerA 25 22 will not be injured.

The contactfinger carrying arm 23 ismounted upon the shaft 29 yand is c lampedthereon' by having one end ,bifurcated and a bolt ,30 passing therethrough so as to draw the parts of the bifurcatedV ends together soas t0 fasten the member firmly upon the shaft 29. The contact'. finger carrying arm 23. also has formed, as an extension thereof, the contact carrying arm stop 3I positioned to abut the stop 32, formed as a projection upon the shaft carrying plate 33.

.The shaft carrying plate 33 is formed with a bearing 34 through which the shaft 29 passes. The shaft 29 extends backwardly from the plate I, as viewed in Fig. 1, or to the left of the panel I, as viewed in Fig. 2. At its farther end, one end of a spirally wound bi-metallic thermo-responsive element 35 is attached, as by means of the screw 36. The bi-metallic member 35 surrounds the shaft and the other end is attached relatively to the plate 33 by means of the clamping bolt 31 which passes through the plate 33, the panel I and the inner end 38 of the bi-metallic member, and is then provided with a threaded end 39 and a nut 40 whereby the inner end of the bi-metallic member is securely held in place.

The bi-metallic member 35 is so positioned upon the shaft 29 and so held, that when thetemperature is relatively high, the shaft 29 is turned so as to bring the contact finger carrying gages with the end 4| of the contact nger 22 and thereby holds it in latched position.

If after the contact linger 22 becomes latched,

as shown in Fig. 1 in full lines, the temperaturefalls to a relatively lower temperature then the shaft 29 will be twisted by the bi-metallic member 35 so as to tend to move contact finger 22 to the left as viewed in Fig. 1. If this continues, the contact :linger carrying arm 23 will, at its lower end, separate from the contact nger 22 bending contact nger 22. This separation is possible because of the spring connection between the contact nger carrying arm 23 and the contact nger 22.

If the contact finger 22 is latched and it is desired to release it, one may manually grasp the manually grasping button it and force it upwardly againstthe spring ld so that contact nger 22 may be released from the latch shoulder 9, if the temperature is such that the shaft 2t is moved to a position such that contact ilnger 22 should be to the left of its position as shown in full lines in Fig. l. i

In Fig. 3 a circuit is shown employing the thermostatic circuit controller of Figs. 1 and 2. In this gure d3 designates a manually operable switch which is shown in the closed position so that current may dow from the positive terminal of a source of potential by wire to through manually operable switch d3, wire 55, resistance d6, wires 41 and 48, coil of electro-magnet 439, wire 50, electro-magnet 4, and wire i to the negative terminal of the source of potential. Current owing in the above traced path energizes electro-magnet 49 and causes its armature 52 to be raised and held raised so that a circuit is formed as follows: positive terminal of a source of potential, wire-44, switch 63, wires 45 and 53,

armature 52 and wire 54, through resistances 55. 56 and 5l to the negative terminal ofthe source of potential. Devices designated 55, 55 and 5l are shown as heating coils and may well be the heating coils used to heat a space within which the thermostatic device designated as a whole by T may be placed and in which a thermostatic device designated by S may also be placed.

-When the electro-magnet 42 is energized and its armature 52 is raised the latch 'i is also raised toward the electro-magnet 4 so that the latch would then stand in practically a horizontal position with its latch shoulder 9 out of position to engage with the contact iinger 22.

If the heat generated by the coils 55, 56,and 5l reaches the bi-metallic thermo-responsive member 35 of the device T, it will cause the contact nger 22` to move to and become latched, as shown in dotted lines in Fig. 3. This would occur because when contact finger 22 touches contact post 2i, a circuit would'loe formed in shunt of the electro-magnet i9 from Wire All, through Wires 52 and 59, latch l, pivot support i9, post 2i, contact nger 22 and Wire t@ vto the negative terminal of the source. This path is a shunt path which is of such resistance as compared with the circuit through the electro-magnet d that electro-magnet it and electro-magnet d would both become cle-energized and armature 52 would drop, cuttingv o the circuit of the heating coils 55, 55 and 5l, and latch lever l would be pushed upwards, so that shoulder 2 would be brought up so as to latch contact finger 22 in its then position. The parts would then remain latched until the thermostatic device had cooled 0E and latch I has been moved upwardly against the spring I4 manually by the manual grasping button i6.

Applicant has also shown another means in Fig. 3 by which current may be cut oi from the coils 55,' 55 and 51. This isv the thermostatic device S, which may also be positioned to be alected by the heat from the heating coils. When the temperature rises high enough the thermostatic device S moves the circuit controller arm 6I into contact with the contacts 52 and $3 thereby forming a shunt path from wire 41 through wires 58 and tt, contact 62, controller arm 6l, contact S3 and wire 55 to the negative terminal ofthe source of potential. This path also would cause a de-energization of electromagnets t9 and il and would thereby cause armature 52 to drop and current be cut off from .the heating coils 55, 56 and 5l, but as soon as the temperature fell the circuit controller arm Gi would be withdrawn from in contact with 22 and t3 and current of suicient value to energize electro-magnets i9 and would again dow so as to lift armature 52 and raise latch against the tension oi' the spring it so that unless the temperature were high enough to cause thermostatic device T to so operate as to bring contact er 22 into contact with stop 2l the relations of the parts would be re-established automatically.

-Although I have particularly described one particular physical embodiment of my invention and explained the operation, construction and principle thereof, nevertheless I desire to have it understood that the form selected is merely illustrative. but does not exhaust the possible physical embodiments of the idea of means underlying my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a thermostatic switch, in combination: a rotatable shaft; a bi-metallic thermo-responsive strip splralled about the shaft, having one end connected to the shaft and the other end nxed; a contact linger adapted for governing a circuit mounted on the shaft to move in one direction therewith; a latch positioned to engage and latch the contact nger; a pivot intermediate the ends of the latch; a compression spring having one end bearing on the portion of the lever on the other side of the pivot from the latch and having its other end bearing against a fixed abutment; manual means for moving the latch out of the path of the contact nger; electro-magnetic means for moving the latch out of the path of the contact inger.

2. In a thermostatic switch, in combination: a rotatable shaft; a loi-metallic thermo-responsive strip spiralled about the shaft, having one end connected to the shaft and the other end dried; a contact :dnger adapted to control a circuit; means for mounting said contact ger upon said shaft whereby the contact nger is positively rotated in one direction of movement ci the shaft and resilientiy in the other direction whereby the contact nger may n s station ary for a predetermined movement of the shaft: and means for the contact ringer to contact with when in one position whereby thereafter the contact linger is held in rotated position regardless of the action of the rotatable shalt.

3. In a thermostatic switch,`in combination: a contact finger; a contact post; thermo-responsive means for moving the contact ilnger into and away from contact with the contact post; a latch positioned to latch the contact finger in contact with the .contact post; a pivot for the latch; a stop for the latch; electro-magnetic means for moving the latch out of position to latch the contact linger; and resilient means positioned to act on the latch to move it into position to latch the contact linger.

4. In a thermostatic switch, in combination: a contact nger; a contact post; thermo-responsive means for moving the contact nger into and away from contact with the contact post; a'latch positioned to latch the lcontact nger in contact with the contact post; a pivot for the' latch; a stop for the latch; manually operable means for moving the latch into position to unlatch the contact linger and resilient means toy move the latch into position to latch the contact finger.

5. Ina thermostatic switch, in combination: a contact ringer; a contact post; thermo-responsive means for moving the contact finger into and away from contact with the contact post; a latch positioned to latch the contact linger in contact with the contact post; aplvotfor the latch; a stop for the latch; biasing means for the latch; an electro-magnet positioned to cooperate with the latch and move the latch out -of latching vposition when energized; a circuit for the electromagnet containing a source o! potential; and means for closing the circuit whereupon the latch is moved outof latching position by the energization of the electro-magnet; -a shunt for the circuit through the electro-magnet including the contact fingerand the contact post whereby when the contact nger and contact post are in engagement current is shunted from the electromagnet and the latch is moved into latching en.

gagement by the biasing means; and manually operable means for moving the latch into position to unlatch the contact linger and thereby break the shunt.

nonna'r J; PAR-sous.

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